TITLE:

VIBRATIONAL STATES ON RELOCALIZATION SURFACES OF HYDROCARBON FREE RADICALS

DATE:

Friday, February 5th, 2010

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Andrew L. Cooksy, Department of Chemistry, San Diego State University

ABSTRACT:

A class of pi-conjugated free radicals, including daughter radicals of acrolein and cyclooctatetraene exhibit potential energy surfaces with distinct, non-equivalent minima, separated by small energy barriers. Many of these radicals are formed as intermediates in hydrocarbon combustion, and isomerize to structures with geometries and spin localizations substantially different from their closed-shell parents. The potential energy surface that couples the minima are characterized by strongly coupled, anharmonic vibrational coordinates, requiring an adaptable, multidimensional analysis for prediction of the vibrational dynamics. Three-dimensional relaxed potential energy surfaces are calculated at the coupled cluster level for selected cases of these isomerizations, extrapolating to the complete basis set limit. The vibrational eigenvalues and eigenvectors are solved on these surfaces using the finite element method,3 and used to predict rovibrational energies and effects of vibrational averaging that may provide experimental probes of the isomerization.

HOST:

Jose Castillo

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